Patent GB-417980-A (GB)
Title: The manufacture of new vat dyestuffs
IPC: C09B1/44
Filed: 1934-03-09
Abstract: Dyes of the general formula <FORM:0417980/IV/1> wherein Ar indicates phenylene or naphthylene, n stands for 1 or 2 and X for S or O, the --CONH-- radicle being attached either to the 2-position and/or to the nucleus Ar, and wherein the latter nucleus as well as the anthraquinone nucleus may contain further substituents, are prepared by condensing mono- or dicarboxylic acids or acid halides of the benzo- or naphtho-thiazole or -oxazole series with a -aminoanthraquinones or by condensing amides of the said carboxylic acids with a -halogenanthraquinones. The products dye yellow to brown shades fast to alkalis and light. In examples, monobenzoyl-1,5-diaminoanthraquinone is condensed with 2-methylbenzthiazole-5- and -6-carboxylic acid chlorides (dyes yellow shades in both cases), 2-phenylbenzthiazole-6-carboxylic acid chloride (dyes yellow), benzthiazole-2-carboxylic acid chloride (dyes yellow), 6-chlorbenzthiazole-2-carboxylic acid chloride (dyes yellow) 6-7-benzobenzthiazole-2-carboxylic acid chloride (yellow), benzoxazole-2-carboxylic acid chloride (reddish-yellow), 2-methylbenzoxazole-5-carboxylic acid chloride (reddish-yellow), 2-phenylbenzoxazole-5-carboxylic acid chloride (yellow), 2-methyl-4,5-benzobenzoxazole-7-carboxylic acid chloride (yellow) and 2-methyl-4,5-benzobenzoxazole-3<1>-carboxylic acid chloride (reddish-yellow); 1-aminoanthraquinone is condensed with 2-phenylbenzthiazole-6-carboxylic acid chloride (greenish-yellow), benzthiazole-2,6-dicarboxylic acid dichloride (greenish-yellow), 2-methylbenzoxazole-5-carboxylic acid chloride (greenish-yellow), 2-phenylbenzoxazole-5-carboxylic acid chloride (greenish-yellow) and 2-methyl-4,5-benzobenzoxazole-7-carboxylic acid chloride (greenish-yellow); 1-chloranthraquinone is condensed with 2-phenylbenzthiazole-6-carboxyl acid amide.  Benzthiazole and benzoxazole carboxylic acids. 2-Phenylbenzthiazole-6-carboxylic acid is prepared by treating p-aminobenzoic acid with disulphurdichloride, splitting the thiazthionium compound and condensing the 1-amino-2-mercaptobenzene-4-carboxylic acid with benzoyl chloride in presence of pyridine.  6-Chlorobenzthiazole-2-carboxylic acid and benzthiazole-2,6-dicarboxylic acid are prepared from 1-amino-2 - mercapto - 4 - chlorbenzene and 1 - amino-2-mercapto - 4 - carboxybenzene respectively by condensation with monochloracetic acid, treatment with sulphuryl chloride and heating with alcohol whereby the six-membered heterocyclic ring is converted to the five-membered ring. 2-Methylbenzoxazole-5-carboxylic acid is prepared by reacting 3-amino-4-oxybenzoic acid with acetic anhydride, and 2-phenylbenzoxazole-5-carboxylic acid by heating the same acid with benzoyl chloride in presence of pyridine.  2 - Methyl -4,5 - benzobenzoxazole - 7 - carboxylic acid is prepared by splitting the azo dye sulphanilic acid --> 2,3-oxynaphthoic acid and reacting the resulting 1-amino-2-oxy-3-naphthoic acid. 2-Methyl-4,5-benzobenzoxazole-3<1>-carboxylic acid is similarly prepared by splitting the azo dye sulphanilic acid --> 2,6-oxynaphthoic acid and condensing with acetic anhydride.